Fuel cell throttle

ABSTRACT

The disclosed technology is generally directed to fuel cells. In one example of the technology, a fuel cell stack that includes an anode and a cathode causes a load to be driven. A control subsystem is measures at least one characteristic associated with the load, and to provide at least one control signal based, at least in part, on the at least one characteristic. An oxidizing agent input subsystem provides an oxidizing agent to the cathode of the fuel cell stack. A fuel input subsystem provides gaseous fuel to the anode of the fuel cell stack. The fuel input subsystem includes a fuel pump that is arranged to pump the gaseous fuel into the fuel input subsystem. A fuel-side high-speed valve adjusts mass flow of the gaseous fuel to the cathode of the fuel cell stack based on at least a first control signal of the at least one control signal.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.16/429,488, filed Jun. 3, 2019, entitled “FUEL CELL THROTTLE” (Atty.Dkt. No. 406501-US-NP). The entirety of this afore-mentioned applicationis incorporated herein by reference.

BACKGROUND

Typically, fuel cells convert chemical energy from a fuel intoelectricity, by using an electrochemical process such as a chemicalreaction of positively charged hydrogen ions or other fuel with oxygenor another oxidizing agent. Fuel cell operation typically depends on twosupplies: a fuel supply which provides an ongoing source of fuel, and anoxidizing agent supply which provides an ongoing source of oxygen orother oxidizing agent to sustain the chemical reaction. The fuel istypically hydrogen, but other fuels may also be used. Various oxidizersmay be used; in some cases, ambient air serves as an oxygen supply.Typically, unlike a battery, which eventually drains and must berecharged before further use as a power source, a fuel cell can produceelectricity continuously as long as the necessary fuel and oxygen aresupplied.

SUMMARY OF THE DISCLOSURE

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Briefly stated, the disclosed technology is generally directed to fuelcells. In one example of the technology, a fuel cell stack includes ananode, a cathode, and an electrolyte that is situated between the anodeand the cathode. In some examples, the fuel cell stack is configured tocause a load to be driven based, at least in part, on a voltagedifference between the anode and the cathode. In some examples, acontrol subsystem is arranged to measure at least one characteristicassociated with the load, and to provide at least one control signalbased, at least in part, on the at least one characteristic. In someexamples, an oxidizing agent input subsystem is arranged to provide anoxidizing agent to the cathode of the fuel cell stack. In some examples,a fuel input subsystem is arranged to provide gaseous fuel to the anodeof the fuel cell stack. In some examples, the fuel input subsystemincludes a fuel pump that is arranged to pump the gaseous fuel into thefuel input subsystem. In some examples, a fuel-side high-speed valve isarranged to adjust mass flow of the gaseous fuel to the cathode of thefuel cell stack based on at least a first control signal of the at leastone control signal.

Other aspects of and applications for the disclosed technology will beappreciated upon reading and understanding the attached figures anddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive examples of the present disclosure aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified. These drawings are not necessarilydrawn to scale.

For a better understanding of the present disclosure, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating an example fuel cell and load;

FIG. 2 is a block diagram illustrating an example of the fuel cell andload of FIG. 1;

FIG. 3 is a block diagram illustrating a portion of an example datacenter in which example fuel cells of FIG. 1 and/or FIG. 2 may be used;

FIG. 4 is a block diagram illustrating one example of a suitablecomputing device; and

FIGS. 5A-5B are a flow diagram illustrating an example of a process forfuel cell throttling, in accordance with aspects of the presentdisclosure.

DETAILED DESCRIPTION

The following description provides specific details for a thoroughunderstanding of, and enabling description for, various examples of thetechnology. One skilled in the art will understand that the technologymay be practiced without many of these details. In some instances,well-known structures and functions have not been shown or described indetail to avoid unnecessarily obscuring the description of examples ofthe technology. It is intended that the terminology used in thisdisclosure be interpreted in its broadest reasonable manner, even thoughit is being used in conjunction with a detailed description of certainexamples of the technology. Although certain terms may be emphasizedbelow, any terminology intended to be interpreted in any restrictedmanner will be overtly and specifically defined as such in this DetailedDescription section. Throughout the specification and claims, thefollowing terms take at least the meanings explicitly associated herein,unless the context dictates otherwise. The meanings identified below donot necessarily limit the terms, but merely provide illustrativeexamples for the terms. For example, each of the terms “based on” and“based upon” is not exclusive, and is equivalent to the term “based, atleast in part, on”, and includes the option of being based on additionalfactors, some of which may not be described herein. As another example,the term “via” is not exclusive, and is equivalent to the term “via, atleast in part”, and includes the option of being via additional factors,some of which may not be described herein. The meaning of “in” includes“in” and “on.” The phrase “in one embodiment,” or “in one example,” asused herein does not necessarily refer to the same embodiment orexample, although it may. Use of particular textual numeric designatorsdoes not imply the existence of lesser-valued numerical designators. Forexample, reciting “a widget selected from the group consisting of athird foo and a fourth bar” would not itself imply that there are atleast three foo, nor that there are at least four bar, elements.References in the singular are made merely for clarity of reading andinclude plural references unless plural references are specificallyexcluded. The term “or” is an inclusive “or” operator unlessspecifically indicated otherwise. For example, the phrases “A or B”means “A, B, or A and B.” As used herein, the terms “component” and“system” are intended to encompass hardware, software, or variouscombinations of hardware and software. Thus, for example, a system orcomponent may be a process, a process executing on a computing device,the computing device, or a portion thereof.

Briefly stated, the disclosed technology is generally directed to fuelcells. In one example of the technology, a fuel cell stack includes ananode, a cathode, and an electrolyte that is situated between the anodeand the cathode. In some examples, the fuel cell stack is configured tocause a load to be driven based, at least in part, on a voltagedifference between the anode and the cathode. In some examples, acontrol subsystem is arranged to measure at least one characteristicassociated with the load, and to provide at least one control signalbased, at least in part, on the at least one characteristic. In someexamples, an oxidizing agent input subsystem is arranged to provide anoxidizing agent to the cathode of the fuel cell stack. In some examples,a fuel input subsystem is arranged to provide gaseous fuel to the anodeof the fuel cell stack. In some examples, the fuel input subsystemincludes a fuel pump that is arranged to pump the gaseous fuel into thefuel input subsystem. In some examples, a fuel-side high-speed valve isarranged to adjust mass flow of the gaseous fuel to the cathode of thefuel cell stack based on at least a first control signal of the at leastone control signal.

In some examples, a fuel cell includes a pump to bring fuel into thesystem and a high-speed valve near the stack to adjust mass flow of thefuel into the stack based detected load changes. In some examples, thisallows the fuel cell to follow load changes relatively quickly, such ason the order of milliseconds.

Illustrative Fuel Cell

FIG. 1 is a diagram of an example of fuel cell 100 and load 130. Fuelcell 100 may be any suitable type of fuel cell. Fuel cell 100 mayinclude fuel cell stack 110, control subsystem 120, fuel input subsystem101, and oxidizing agent input subsystem 102. Fuel cell stack no mayinclude anode in, cathode 112, and electrolyte 113. Fuel input subsystem101 may include fuel pump 141 and fuel-side high-speed valve 151.

In fuel cell stack 110, in some examples, electrolyte 113 is situatedbetween anode in and cathode 112. Fuel cell stack no may be configuredto cause load 130 to be driven based, at least in part, on a voltagedifference between anode in and cathode 112. In some examples, fuel cellstack no is in a hot box and is at a substantially higher temperaturethan the rest of fuel cell 100 during normal fuel cell operation. Fuelcell stack no may receive a fuel from fuel input subsystem 101 and anoxidizing agent from oxidizing agent subsystem 102. The internal fuelmay be, for example, hydrogen, carbon monoxide, or the like. In someexamples, the external fuel provided may a fuel that reacts inside thehot box to provide the internal fuel—for instance, in some examples, theexternal fuel may be a hydrocarbon such as methane that reacts to formhydrogen and carbon monoxide, and in turn hydrogen and carbon monoxideact as the internal fuel.

The oxidizing agent may be, for example, oxygen or an oxide. Theoxidizing agent may be a gas, such as air, that includes oxygen. Thefuel cell stack may rely upon a chemical reaction, such as thecombination of hydrogen and oxygen to form water, or the reaction ofcarbon monoxide and oxygen to form carbon dioxide.

Electrolyte 113 may allow ions to move between anode 111 and cathode 112of fuel cell stack no. At anode in, a catalyst may cause the fuel toundergo oxidation reactions that generate ions and electrons. The ionsmay move from anode in to cathode 112 through electrolyte 113. At thesame time, electrons may flow from anode in to cathode 112 through load130, producing a current. At cathode 112, another catalyst may causeions, electrons, and the oxidizing agent to react, forming outputs ofthe chemical reaction, such as water in the case of hydrogen and oxygen.During operation, cell stack no may provide a voltage drop of about 0.7V between anode in and cathode 112, where the voltage drop may varybased on the load and other factors.

Control subsystem 120 is arranged, in some examples, to measure at leastone characteristic associated with load 130, such as current, voltage,and/or the like, and to provide one or more control signals based, atleast in part, on the measured characteristics. In some examples, alook-up table may be used to provide one or more of the control signalsbased on the measured characteristics.

In some examples, oxidizing agent input subsystem 102 is arranged toprovide the oxidizing agent to cathode 112 of fuel cell stack no. Insome examples, fuel input subsystem 101 is arranged to provide the fuelto cathode in of fuel cell stack no. In some examples, fuel pump 141 isarranged to pump the fuel into fuel input subsystem 101, where the fuelis a gaseous fuel. In some examples, fuel-side high-speed valve 151 isarranged to adjust mass flow of the gaseous fuel to anode of the stackbased on at least one of the control signals (e.g., control signal CTL)provided by control subsystem 120. For instance, in some examples,fuel-side high speed valve 151 is controlled to adjust the mass flow ofthe fuel provided to fuel cell stack 110 based on the load current andload voltage, with those values provided to a look-up table, so that achange in load is followed relatively quickly, such as in a time frameof milliseconds.

FIG. 2 is a diagram of an example of fuel cell 200 and load 230, whichmay be examples of fuel cell 100 and load 130 of FIG. 1. Fuel cell 200may include fuel cell stack 210, control subsystem 220, fuel inputsubsystem 201, and oxidizing agent input subsystem 202. Fuel cell stack210 may include anode 211, cathode 212, and electrolyte 213. Fuel inputsubsystem 201 may include fuel pump 241, pressure regulator 243, fuelaccumulator 261, fuel-side high-speed valve 251, and heated nitrogenpurge subsystem 271. Oxidizing agent input subsystem 202 may includeoxidizing agent pump 242, pressure regulator 244, oxidizing agentaccumulator 262, and oxidizing-agent-side high-speed valve 252.

In some examples, fuel pump 241 and oxidizing agent pump 242 arevariable speed pumps, with the speed of fuel pump 241 linked with thespeed of oxidizing agent pump 242, with each being controlled based onone of the control signals provided by control subsystem 220. In someexamples, fuel pump 241 is arranged to increase the pressure of the fuelfrom the fuel inlet into fuel cell 200, and oxidizing agent pump 242 isarranged to increase the pressure of the oxidizing agent from theoxidizing agent inlet into fuel cell 200. Fuel input subsystem 201 mayinclude one or more pipes through which the gaseous fuel passes, andoxidizing input subsystem 202 may include one or more pipes throughwhich the oxidizing agent, such as air or a solid oxide, passes.

In some examples, pressure regulator 243 is arranged to regulate thepressure of the fuel into fuel cell 200, and pressure regulator 244 isarranged to regulate the pressure of the oxidizing agent into fuel cell200. In some examples, pressure regulator 243 is part of a return linethat bypasses around pump 241 to ensure that flow of fuel into fuel cell200 is the correct volume and ratio. In some examples, pressureregulator 244 is part of a return line that bypasses around pump 242 toensure that flow of oxidizing agent into fuel cell 200 is the correctvolume and ratio. In some examples, pressure regulator 243 is part offuel pump 241, and in other examples, pressure regulator 243 is separatefrom fuel pump 241. Similarly, in some examples, pressure regulator 244is part of fuel pump 242, and in other examples, pressure regulator 244is separate from fuel pump 242.

In some examples, fuel-side high-speed valve 251 is arranged to controlmass flow of the fuel to fuel cell stack 210 based on control providedby control subsystem 220. In some examples, oxidizing-agent-sidehigh-speed valve 252 is arranged to control mass flow of the oxidizingagent to fuel cell stack 210 based on control provided by controlsubsystem 220. The control provided to high-speed valves 251 and 252 maybe provided by control subsystem 220 via feedback based on load 230,such as by pulse width modulation (PWM) or other suitable type offeedback. In some examples, the control provided to high-speed valve 251and high-speed valve 252 are mechanically and/or electrically linked. Inthis way, in some examples, high-speed valve 251 and high-speed valve252 are synchronized with each other. One example of mechanical linkagewould be one actuator controlling both high-speed valve 251 andhigh-speed valve 252. High-speed valve 251 and/or high-speed valve 252may each be a high-speed needle valve, a high-speed butterfly valve, orother suitable high-speed valve.

In some examples, the high-speed valves 251 and 252 are each close tofuel cell stack 210. In some examples, each high-speed valve (251 and252) includes an actuator that is outside of the hot box, along with along shaft or plunger that goes inside the hot box, opening up into avalve inside the hot box, so that the opening of the high-speed valve isinside the hot box. The actuator may include electronics, a motor thatturns the valve, and/or the like. Also, control associated with thehigh-speed valve may be outside of the hot box.

As discussed above, in some examples, the hot box contains the fuel cellstack 210, which reacts at a high temperature, with the heat box being awell-insulated containing the high-temperature stack and providinginsulative protection from high temperatures to the rest of the fuelcell, keeping the heat inside the hot box during operation of the fuelcell. In some examples, the electronics are kept outside of the hot box.In some examples, pumps 141 and 142 are also kept a certain distanceaway from the hot box to avoid having pumps 141 and 142 from being athigh temperature during fuel cell operation. That is, in some examples,while high-speed valves 251 and 252 are quite close to the fuel cellstack 210, almost right at the input of fuel cell stack 210, pumps 241and 242 are relatively far from fuel cell stack 210.

Accumulator 261 may be arranged to handle pressure drops during theopening of valve 251 and the ramping up of pump 241 during high-speedload demand changes. Accumulator 261 stores fuel as high pressure. Inthis way, for example, if the pressure drops suddenly because the flowat valve 251 is open, accumulator 261 can provide additional pressure,or an additional buffer of fuel. In this way, in some examples, valve251 and accumulator 261 work together to enable fuel cell 200 to adjustto rapid changes in the load—when valve 251 is open, a pressure drop mayoccur, and accumulator 261 may provide additional volume to ensure thatthe fuel can ramp up and compensate in time. Because the fuel isgaseous, in some examples, when the fuel is pressurized, the gas iscompressed, so that it is possible to get more fuel mass through thepipe in fuel input subsystem 201.

Accumulator 262 may operate in a similar manner on the oxidizing agentside to provide an additional buffer of oxidizing agent, for examplewhen the flow at valve 252 is open.

In some examples, a parallel fuel input may used instead of or inaddition to accumulator 261. The parallel fuel input may provide asecond path for fuel that joins the main path right near anode 211 offuel cell stack 210, that opens up and begins injecting higher pressurefuel there if the load increases very quickly, and a staged system maybe used in some examples.

In some examples, heated nitrogen purge subsystem 271 may be used to“de-throttle” fuel cell 200 in the event of an instantaneous loss ofload, so as to prevent excess fuel from passing through the system. Insome examples, heated nitrogen purge subsystem 271 may also be used inthe event of a sudden and significant drop in the load, with the amountof heated nitrogen provided based on the drop in load as detected bycontrol subsystem 120. In some examples, heated nitrogen purge subsystem271 is used upon shutdown of fuel cell 100 to ensure that no furtherpower is generated. Although FIG. 2 specifically shows a heated nitrogenpurge subsystem, in other examples, a different purge subsystem may beemployed, so that an inert gas other than nitrogen may be used for thepurge.

As discussed above, control subsystem 220 may provide one or morecontrol signals based on load current, load voltage, and/or the like. Insome examples, other factors such as temperature of fuel cell stack 210,volumetric measurements on the oxidizing agent side, differentialpressure, fuel flows, and/or the like may also be used by controlsubsystem 220, particularly for control of the oxidizing agent side. Insome examples, pressure sensors may be used throughout the pipes on thefuel side and the oxidizing agent side and provide the output of thepressure sensors to control subsystem 220. Control subsystem 220 mayprovide control to both the fuel side and the oxidizing-agent side. Insome examples, control of the oxidizing-agent side may ensure that nolarge pressure differential develops between the fuel side and theoxidizing-agent side.

Fuel cell stack 210 may output unused fuel, unused oxidizing agent, andone or more outputs of the chemical reaction, such as, for example,water. Although not shown in FIG. 2, rather than providing the voltagedrop across anode 211 and cathode 212 directly to load 230, in someexamples, a power regulator is first used to ensure that the output DCvoltage is relatively constant, and the constant DC voltage output isapplied to the stack. In some examples, where output AC power isrequired, an AC/DC converter may be used to convert the power to ACpower before being applied to the load. In some examples, the outputvoltages of multiple stacks from multiple fuel cells may be connected inseries. For instance, in some examples, a number of fuel cells may eachprovide a voltage drop across the respective anode and diodes of thefuel cell stack, with the voltage drop provided to a voltage regulatorto provide a substantially constant voltage, with the voltage output ofeach of the power regulators coupled together to provide a combinedvoltage output that is provided across a load. When the load changes,each of the fuel cells may then follow the load accordingly at a rangeof speed of milliseconds based on the variable-speed pumps,accumulators, and high-speed valves present in each of the fuel cellsthat each provide a portion of the voltage to the load.

Fuel cell 210 may be used in any suitable fuel cell context,particularly a fuel cell context where dynamic load changes may occur.One example application for fuel cell 210 is for use in a data center,as shown below in accordance with one example in FIG. 3.

Illustrative Data Center

FIG. 3 is a diagram of a portion (305) of an example data center.Portion 305 may include fuel cells 300, batteries 389, voltageregulators 381, voltage regulators 382, DC racks 378, and AC racks 379.In some examples, data center services are provided by server racksincluding DC racks 378 and AC racks 379, where the fuel cells 300 areused as the power source for the server racks. Each fuel cell 300 has acorresponding battery 389 for fuel cell 300 in some examples. Voltageregulators 381 are used at the output of batteries 389 in some examples.

In some examples, the output of each fuel cell 300 goes to acorresponding voltage regulator 382, to provide a constant voltageoutput responsive to the received voltage output by the correspondingfuel cell 300. In some examples, the output of voltage regulators 382are used to power DC racks 378 and AC racks 379, where each of the ACracks include a DC/AC converter. In the examples illustrated, a commonfuel line comes in to provide gaseous fuel to each of the fuel cells300. The gaseous fuel may be hydrogen gas, carbon monoxide gas, a fuelsource that will react in fuel cell 300 to form a suitable fuel in thehot box of the fuel cell 300, or the like. In some examples, the serverracks are powered on a row-by-row basis, with a row of server racksconnected to a row of fuel cells. Other suitable arrangements are usedin other examples.

FIG. 3 shows a particular example of a portion of an example datacenter. Various other examples of the disclosure may include more orless components than shown, and may vary according to various suitablemanners.

Illustrative Computing Device

FIG. 4 is a diagram illustrating one example of computing device 400 inwhich aspects of the technology may be practiced. Computing device 400may be virtually any type of general- or specific-purpose computingdevice. In some examples, computing device 400 may be an example of aportion of control subsystem 220 of FIG. 2 and or control subsystem 120of FIG. 1. As illustrated in FIG. 4, computing device 400 includesprocessing circuit 410, operating memory 420, memory controller 430,data storage memory 450, input interface 460, output interface 470, andnetwork adapter 480. Each of these afore-listed components of computingdevice 400 includes at least one hardware element.

Computing device 400 includes at least one processing circuit 410configured to execute instructions, such as instructions forimplementing the herein-described workloads, processes, or technology.Processing circuit 410 may include a microprocessor, a microcontroller,a graphics processor, a coprocessor, a field-programmable gate array, aprogrammable logic device, a signal processor, or any other circuitsuitable for processing data. Processing circuit 410 is an example of acore. The aforementioned instructions, along with other data (e.g.,datasets, metadata, operating system instructions, etc.), may be storedin operating memory 420 during run-time of computing device 400.Operating memory 420 may also include any of a variety of data storagedevices/components, such as volatile memories, semi-volatile memories,random access memories, static memories, caches, buffers, or other mediaused to store run-time information. In one example, operating memory 420does not retain information when computing device 400 is powered off.Rather, computing device 400 may be configured to transfer instructionsfrom a non-volatile data storage component (e.g., data storage component450) to operating memory 420 as part of a booting or other loadingprocess.

Operating memory 420 may include 4^(th) generation double data rate(DDR4) memory, 3^(rd) generation double data rate (DDR3) memory, otherdynamic random-access memory (DRAM), High Bandwidth Memory (HBM), HybridMemory Cube memory, 3D-stacked memory, static random-access memory(SRAM), or other memory, and such memory may comprise one or more memorycircuits integrated onto a DIMM, SIMM, SODIMM, or other packaging. Suchoperating memory modules or devices may be organized according tochannels, ranks, and banks. For example, operating memory devices may becoupled to processing circuit 410 via memory controller 430 in channels.One example of computing device 400 may include one or two DIMMs perchannel, with one or two ranks per channel. Operating memory within arank may operate with a shared clock, and shared address and commandbus. Also, an operating memory device may be organized into severalbanks where a bank can be thought of as an array addressed by row andcolumn. Based on such an organization of operating memory, physicaladdresses within the operating memory may be referred to by a tuple ofchannel, rank, bank, row, and column.

Despite the above-discussion, operating memory 420 specifically does notinclude or encompass communications media, any communications medium, orany signals per se.

Memory controller 430 is configured to interface processing circuit 410to operating memory 420. For example, memory controller 430 may beconfigured to interface commands, addresses, and data between operatingmemory 420 and processing circuit 410. Memory controller 430 may also beconfigured to abstract or otherwise manage certain aspects of memorymanagement from or for processing circuit 410. Although memorycontroller 430 is illustrated as single memory controller separate fromprocessing circuit 410, in other examples, multiple memory controllersmay be employed, memory controller(s) may be integrated with operatingmemory 420, or the like. Further, memory controller(s) may be integratedinto processing circuit 410. These and other variations are possible.

In computing device 400, data storage memory 450, input interface 460,output interface 470, and network adapter 480 are interfaced toprocessing circuit 410 by bus 440. Although, FIG. 4 illustrates bus 440as a single passive bus, other configurations, such as a collection ofbuses, a collection of point to point links, an input/output controller,a bridge, other interface circuitry, or any collection thereof may alsobe suitably employed for interfacing data storage memory 450, inputinterface 460, output interface 470, or network adapter 480 toprocessing circuit 410.

In computing device 400, data storage memory 450 is employed forlong-term non-volatile data storage. Data storage memory 450 may includeany of a variety of non-volatile data storage devices/components, suchas non-volatile memories, disks, disk drives, hard drives, solid-statedrives, or any other media that can be used for the non-volatile storageof information. However, data storage memory 450 specifically does notinclude or encompass communications media, any communications medium, orany signals per se. In contrast to operating memory 420, data storagememory 450 is employed by computing device 400 for non-volatilelong-term data storage, instead of for run-time data storage.

Also, computing device 400 may include or be coupled to any type ofprocessor-readable media such as processor-readable storage media (e.g.,operating memory 420 and data storage memory 450) and communicationmedia (e.g., communication signals and radio waves). While the termprocessor-readable storage media includes operating memory 420 and datastorage memory 450, the term “processor-readable storage media” (whetherin the plural or singular form), throughout the specification and theclaims, is defined herein so that the term “processor-readable storagemedia” specifically excludes and does not encompass communicationsmedia, any communications medium, or any signals per se. However, theterm “processor-readable storage media” does encompass processor cache,Random Access Memory (RAM), register memory, and/or the like.

Computing device 400 also includes input interface 460, which may beconfigured to enable computing device 400 to receive input from users orfrom other devices. In addition, computing device 400 includes outputinterface 470, which may be configured to provide output from computingdevice 400. In one example, output interface 470 includes a framebuffer, graphics processor, graphics processor or accelerator, and isconfigured to render displays for presentation on a separate visualdisplay device (such as a monitor, projector, virtual computing clientcomputer, etc.). In another example, output interface 470 includes avisual display device and is configured to render and present displaysfor viewing. In yet another example, input interface 460 and/or outputinterface 470 may include a universal asynchronous receiver/transmitter(“UART”), a Serial Peripheral Interface (“SPI”), Inter-IntegratedCircuit (“I2C”), a General-purpose input/output (GPIO), and/or the like.Moreover, input interface 460 and/or output interface 470 may include orbe interfaced to any number or type of peripherals.

In the illustrated example, computing device 400 is configured tocommunicate with other computing devices or entities via network adapter480. Network adapter 480 may include a wired network adapter, e.g., anEthernet adapter, a Token Ring adapter, or a Digital Subscriber Line(DSL) adapter. Network adapter 480 may also include a wireless networkadapter, for example, a Wi-Fi adapter, a Bluetooth adapter, a ZigBeeadapter, a Long-Term Evolution (LTE) adapter, or a 5G adapter.

Although computing device 400 is illustrated with certain componentsconfigured in a particular arrangement, these components and arrangementare merely one example of a computing device in which the technology maybe employed. In other examples, data storage memory 450, input interface460, output interface 470, or network adapter 480 may be directlycoupled to processing circuit 410, or be coupled to processing circuit410 via an input/output controller, a bridge, or other interfacecircuitry. Other variations of the technology are possible.

Some examples of computing device 400 include at least one memory (e.g.,operating memory 420) adapted to store run-time data and at least oneprocessor (e.g., processing unit 410) that is adapted to executeprocessor-executable code that, in response to execution, enablescomputing device 400 to perform actions.

Illustrative Process

FIGS. 5A-5B illustrate an example dataflow for a process (590) for afuel cell. In some examples, process 590 is performed by a device, suchas fuel cell 100 of FIG. 1, fuel cell 200 of FIG. 2, or one or more ofthe fuel cells 300 of FIG. 3.

In the illustrated example, step 591 occurs first. At step 591, in someexamples, a load is caused to be driven based, at least in part, on avoltage difference between an anode and a cathode of a fuel cell stackof a fuel cell. As shown, step 592 occurs next in some examples. At step592, in some examples, at least one characteristic associated with theload is measured. As shown, step 593 occurs next in some examples. Atstep 593, in some examples, at least one control signal is providedbased, at least in part, on the at least one characteristic.

As shown, step 594 occurs next in some examples. At step 594, in someexamples, an oxidizing agent is provided to the cathode of the fuel cellstack. As shown, step 595 occurs next in some examples. At step 595, insome examples, gaseous fuel is pumped into the anode of the fuel cellstack. As shown, step 596 occurs next in some examples. At step 596, insome examples, mass flow of the gaseous fuel to the cathode of the fuelcell stack is adjusted based on at least a first control signal of theat least one control signal. The process may then advance to the returnblock, where other processing is resumed.

CONCLUSION

While the above Detailed Description describes certain examples of thetechnology, and describes the best mode contemplated, no matter howdetailed the above appears in text, the technology can be practiced inmany ways. Details may vary in implementation, while still beingencompassed by the technology described herein. As noted above,particular terminology used when describing certain features or aspectsof the technology should not be taken to imply that the terminology isbeing redefined herein to be restricted to any specific characteristics,features, or aspects with which that terminology is associated. Ingeneral, the terms used in the following claims should not be construedto limit the technology to the specific examples disclosed herein,unless the Detailed Description explicitly defines such terms.Accordingly, the actual scope of the technology encompasses not only thedisclosed examples, but also all equivalent ways of practicing orimplementing the technology.

We claim:
 1. An apparatus, comprising: at least one memory storingprocessor-executable code therein, and at least one processor that isadapted to execute the processor-executable code, wherein theprocessor-executable code includes processor-executable instructionsthat, in response to execution, enables the apparatus to performactions, including: measuring at least one characteristic associatedwith a load that is driven based, at least in part, on a voltagedifference between an anode and a cathode of a fuel cell stack of a fuelcell, wherein the at least one characteristic associated with the loadis at least one of a voltage of the load or a current of the load;controlling pumping of gaseous fuel into the fuel cell; and providing atleast one control signal based, at least in part, on the at least onecharacteristic, such that a first control signal of the at least onecontrol signal causes an adjustment of mass flow of the gaseous fuel tothe anode of the fuel cell stack.
 2. The apparatus of claim 1, theactions further including: storing the gaseous fuel; and providing thestored gaseous fuel to the fuel cell stack responsive to a drop inpressure in the gaseous fuel being pumped into the fuel cell.
 3. Theapparatus of claim 1, the actions further including: causing anadjustment of a speed of the pumping of the gaseous fuel into the fuelcell stack based, at least in part, on a second control signal of the atleast one control signal.
 4. The apparatus of claim 1, the actionsfurther including: providing an inert gas to the anode of the fuel cellstack responsive to another control signal of the at least one controlsignal.
 5. The apparatus of claim 1, the actions further including:using a hot box that surrounds the fuel cell stack to insulatecomponents outside of the hot box from high temperature inside the hotbox.
 6. The apparatus of claim 1, the actions further including:controlling pumping of an oxidizing agent into the cathode of the fuelcell stack.
 7. The apparatus of claim 6, wherein controlling the pumpingof the oxidizing agent includes adjusting a speed of the pumping of theoxidizing agent, based, at least in part, on at least one signal of theat least one control signal, wherein the actions further includeadjusting a speed of the pumping of the gaseous fuel into the fuel cell,based, at least in part, on at least one control signal of the at leastone control signal, and wherein the speed of the pumping of theoxidizing agent and the speed of the pumping of the gaseous fuel arelinked.
 8. The apparatus of claim 6, the actions further includingadjusting a mass flow of the oxidizing agent into the cathode of thefuel cell stack based on at least one of the signals of the at least onecontrol signal.
 9. A method, comprising: measuring at least onecharacteristic associated with a load that is driven based, at least inpart, on a voltage difference between an anode and a cathode of a fuelcell stack of a fuel cell, wherein the at least one characteristicassociated with the load is at least one of a voltage of the load or acurrent of the load; controlling pumping of gaseous fuel into the fuelcell; and providing at least one control signal based, at least in part,on the at least one characteristic, such that a first control signal ofthe at least one control signal causes an adjustment of mass flow of thegaseous fuel to the anode of the fuel cell stack.
 10. The method ofclaim 9, further comprising: storing the gaseous fuel; and providing thestored gaseous fuel to the fuel cell stack responsive to a drop inpressure in the gaseous fuel being pumped into the fuel cell.
 11. Themethod of claim 9, further comprising: causing an adjustment of a speedof the pumping of the gaseous fuel into the fuel cell stack based, atleast in part, on a second control signal of the at least one controlsignal.
 12. The method of claim 9, further comprising: storing thegaseous fuel; and providing the stored gaseous fuel to the fuel cellstack responsive to a drop in pressure in the gaseous fuel being pumpedinto the fuel cell.
 13. The method of claim 9, further comprising:providing an inert gas to the anode of the fuel cell stack responsive toanother control signal of the at least one control signal.
 14. Themethod of claim 9, further comprising: controlling pumping of anoxidizing agent into the cathode of the fuel cell stack.
 15. Aprocessor-readable storage medium, having stored thereonprocessor-executable code that, upon execution by at least oneprocessor, enables actions, comprising: measuring at least onecharacteristic associated with a load that is driven based, at least inpart, on a voltage difference between an anode and a cathode of a fuelcell stack of a fuel cell, wherein the at least one characteristicassociated with the load is at least one of a voltage of the load or acurrent of the load; controlling pumping of gaseous fuel into the fuelcell; and providing at least one control signal based, at least in part,on the at least one characteristic, such that a first control signal ofthe at least one control signal causes an adjustment of mass flow of thegaseous fuel to the anode of the fuel cell stack.
 16. Theprocessor-readable storage medium of claim 15, the actions furthercomprising: causing an adjustment of a speed of the pumping of thegaseous fuel into the fuel cell stack based, at least in part, on asecond control signal of the at least one control signal.
 17. Theprocessor-readable storage medium of claim 15, the actions furthercomprising: causing an adjustment of mass flow of an oxidizing agent toa cathode of the fuel cell stack based on at least the first controlsignal such that the adjustment of the mass flow of the oxidizing agentto the anode of the fuel cell stack is linked with the adjustment of thegaseous fuel to the cathode of the fuel cell stack.
 18. Theprocessor-readable storage medium of claim 15, the actions furthercomprising: storing the gaseous fuel; and providing the stored gaseousfuel to the fuel cell stack responsive to a drop in pressure in thegaseous fuel being pumped into the fuel cell.
 19. The processor-readablestorage medium of claim 15, the actions further comprising: providing aninert gas to the anode of the fuel cell stack responsive to anothercontrol signal of the at least one control signal.
 20. Theprocessor-readable storage medium of claim 15, the actions furthercomprising: controlling pumping of an oxidizing agent into the cathodeof the fuel cell stack.